Human joints, in particular the knee, hip, shoulder, ankle, and spine, are susceptible to degeneration from disease, trauma, and long-term repetitive use that eventually lead to pain. Joint pain arising from osteoarthritis, for example, is the impetus for a wide majority of medical treatments and associated medical costs. The most popular theory arising from the medical community is that joint pain results from bone-on-bone contact or inadequate cartilage cushioning. These conditions are believed to frequently result from the progression of osteoarthritis, which is measured in terms of narrowing of the joint space. Therefore, the severity of osteoarthritis is believed to be an indicator or precursor to joint pain. Most surgeons and medical practitioners thus base their treatments for pain relief on this theory. For example, the typical treatment is to administer pain medication, or more drastically, to perform some type of joint resurfacing or joint replacement surgery.
However, the severity of osteoarthritis, especially in joints such as the knee and ankle, has been found to correlate poorly with the incidence and magnitude of the pain. Because of this, surgeons and medical practitioners have struggled to deliver consistent, reliable pain relief to patients, especially if preservation of the joint is desired.
Whether by external physical force, disease, or the natural aging process, structural damage to bone can cause injury, trauma, degeneration or erosion of otherwise healthy tissue. The resultant damage can be characterized as a bone defect that can take the form of a fissure, fracture, microfracture, lesion, edema, tumor, or sclerotic hardening, for example. Particularly in joints, the damage may not be limited to a bone defect, and may also include cartilage loss (especially articular cartilage), tendon damage, and inflammation in the surrounding area.
Patients most often seek treatment because of pain and deterioration of quality of life attributed to the osteoarthritis. The goal of surgical and non-surgical treatments for osteoarthritis is to reduce or eliminate pain and restore normal joint function. Both non-surgical and surgical treatments are currently available for joint repair.
The technique of subchondrally treating joints affected by osteoarthritis (OA) to relieve the associated pain, as well as treat the underlying disease, has been previously described by applicants. This subchondral treatment involves the stabilization and/or stimulation of the subchondral space at the area of the joint damaged by osteoarthritis, while also preserving as much as possible the articular surface of the joint. This subchondral treatment may be applied to all joints of the human body, including smaller joints such as ankle, elbow, or wrist joints.
In some cases, the ease with which the subchondral treatment developed by applicants is administered depends in large part on the instrumentation that is available to effect the treatment. One of the setbacks of using currently available surgical access devices and insertion tools is the lack of ability to target a specific area of the bone to be treated in a fast, accurate, easy and controlled manner. Presently, in order to treat or repair a bone defect at a joint, the surgeon often has to take multiple steps using multiple surgical tools in order to access, locate, and treat the target defect site. Even so, the surgeon does not have a reliable instrument or system that would allow him to easily and quickly target an area such as the subchondral region of a joint, and either deliver to, or remove material from, that target region. In order to perform repeated or multiple procedures in the same defect location with the currently available tools, additional and unnecessary time in the operating room would be required, as well as an increased risk for complications since numerous instruments and maneuvers are at play.
In the particular case of an ankle joint, the key bone is called the talus, or astralagus, bone. This is a small bone that sits between the heel bone (calcaneus) and the two bones of the lower leg (tibia and fibula). The talus has an irregular, humped shape, similar to that of a turtle. The bones of the lower leg articulate on top and around the sides to form the ankle joint. Where the talus meets the bones of the foot, it forms the subtalar joint, which is important for walking on uneven ground. Thus, the talus is an important connector between the foot and the leg and body, helping to transfer weight and pressure forces across the ankle joint. It is also for this reason that the talus is susceptible to fracture and degradation from osteoarthritis.
Due to the uniquely curved shape of the talus, subchondral treatment of the ankle joint may be challenging. In particular, precise, controlled and repeatable targeting of the subchondral region of the talus bone may be particularly difficult due to the inherent natural topography (i.e., curvature) of the bone. Accordingly, it is desirable to provide instruments that allow fast, easy, and controllable surgical access to the target site, or the bone defect within these small joints, to be treated. Even more desirable are instruments that allow reliable, repeatable and precise targeting and navigation to the subchondral target area of these small joints, such as the ankle joint. Thus, what are needed are instruments for subchondral treatment of small joints that accommodate their anatomy, and allow for treatment with ease, repeatability and accuracy.